In the past, optically active .alpha.-tocopherol and derivatives thereof which are the 2R,4'R,8'R isomers of compounds of the formula: ##STR1## have been prepared through isolation from natural sources such as vegetable oil. This procedure suffers from many drawbacks due to the fact that the tocopherol content of these oils is very small. Therefore, a great amount of oil must be processed in order to isolate a small amount of natural tocopherol. Additionally, the process whereby various tocopherols are isolated from vegetable oil is extremely cumbersome.
In U.S. patent application Ser. No. 417,465, filed Nov. 19, 1973, Scott et al., natural .alpha.-tocopherol has been synthesized by reacting via a Wittig reaction a compound of the formula: ##STR2##
wherein R taken together with its attached oxygen atom forms an ether or ester protecting group removable by hydrogenation or hydrolysis.
(Please note the compound of formula XXVII-A in U.S. application Ser. No. 417,465, filed Nov. 19, 1973) with a dodecanol of the formula: ##STR3## (Please note compound XLVIII-B in U.S. application Ser. No. 417,465). A disadvantage of this process is that the dodecanol of formula III has been difficult to synthesize asymmetrically. In the past, this dodecanol has been produced through degradation of naturally occurring materials such as phytol.